Bathroom Ventilation Duct Recuperation With Cyclic Fan Control
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Solution Overview
Problem
Existing ventilation devices for interior rooms, such as bathrooms, suffer from significant heat losses and uncomfortable temperature fluctuations due to vertical air ducts, which can lead to condensation and noise issues from fan operation.
Innovation Solution
A simplified ventilation system with two air ducts, one vertically above the room and one in the basement, utilizing a heat and humidity exchanger integrated into the air duct's inner surface, with a fan control system adjusted based on temperature and humidity sensors to optimize recuperation cycles and air exchange.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a vertical ventilation line with air ducts is used to discharge heated moist air upwards, then the ventilation function is achieved, but significant heat losses occur and cold air entering from below causes uncomfortably low temperatures and condensation
Solution Approach 1:
The fan operates in periodic cycles, alternating between extracting moist air from the room and admitting fresh air through the same air duct. This periodic operation allows the air duct to be charged with heat during the extraction phase and discharged during the fresh air admission phase, reducing heat losses and preventing condensation while maintaining ventilation effectiveness.
2Loss of energy
If a short ventilation duct through the outer wall with a heat and humidity exchanger is used, then heat recovery is improved, but the fan noise creates uncomfortable loads
Solution Approach 1:
The system uses periodic fan operation with recuperation cycles instead of continuous operation. The fan runs in short intervals to exchange air between the room and outside, allowing the heat and humidity exchanger to recuperate during operation while minimizing noise exposure time. This periodic approach reduces the overall noise load on occupants while maintaining effective heat recovery.
3Loss of energy
If the fan running time is extended to allow sufficient heat and moisture exchange, then recuperation effectiveness is improved, but energy consumption increases
Solution Approach 1:
The fan operates in periodic cycles with optimized duration to achieve sufficient heat and moisture exchange between air masses. The periodic operation allows the exchanger to recuperate heat and humidity during each cycle, achieving effective air exchange without requiring excessively long running times that would waste energy. The cycle timing is optimized to balance recuperation effectiveness with energy consumption.
4Loss of energy
If temperature sensors are used to precisely regulate the recuperation cycle, then heat recovery efficiency is improved, but device complexity increases
Solution Approach 1:
Temperature sensors are positioned at the air opening and in the room to detect temperature differences and regulate the fan operation accordingly. When the temperature difference indicates sufficient heat exchange has occurred, the control system stops the fan cycle. This feedback mechanism optimizes heat recovery efficiency by preventing unnecessary fan operation while maintaining simple and practical control implementation.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration reduces heat losses, minimizes noise, and enhances ventilation efficiency by precisely regulating the fan operation and air exchange, ensuring effective heat and moisture recovery while maintaining a comfortable indoor environment with reduced effort and cost.
Implementation Method 1
heat conduction and heat storage and due to the duration of the loading and unloading processes takes place on the surface and in the near-surface area of the air line
Implementation Method 2
due to the adsorption properties of water vapor and heat conduction and heat storage
Implementation Method 3
a fan, whose recuperation capacity is used to match the recuperation cycle and thus the running time of the fan to the required recuperation capacity
Data Source
Figure 1
Figure 2
AI summary
Ventilation device for changing the air in rooms (4), in particular bathrooms in buildings, each with two air ducts (1, 1') which are each connected to a room (4) or a room group via an air opening (5, 5'). consisting in particular of a single ventilation line (7) which is located in the area of the room (4) or the group of rooms and is interrupted there and runs essentially vertically, with each air duct (1, 1') being provided with a recuperation arrangement which is at least an exchanger (2, 2') for heat and humidity, and a ventilator (3, 3'), at whose recuperation capacity the recuperation cycle and thus the running time of the ventilator (3, 3') is adapted to the required recuperation performance and the inner surface of the air line (1, 1'), at least in part, forms the storage surface of the exchanger (2, 2') for the recuperation of heat and humidity.